Display apparatus and portable terminal

ABSTRACT

A display apparatus includes a first base plate, a second base plate coupled to the first base plate to allow the second base plate to be rotated on the basis of a rotation axis between the first base plate and the second base plate, a moving plate coupled to the second base plate and configured to slide along a first direction with respect to the second base plate, a pop-up plate configured to move along a second direction corresponding to a thickness direction of the second base plate on the second base plate in accordance with a movement of the moving plate, and a display panel including a first portion coupled to the first base plate and a second portion coupled to the moving plate.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/716,199, filed Sep. 26, 2017, which is a continuation of U.S. patentapplication Ser. No. 15/176,135, filed Jun. 7, 2016, now U.S. Pat. No.9,778,682, which claims priority to and the benefit of Korean PatentApplication No. 10-2015-0110728, filed Aug. 5, 2015, the entire contentof all of which is incorporated herein by reference.

BACKGROUND 1. Field

Aspects of embodiments of the present invention relate to a displayapparatus and a portable terminal. More particularly, aspects ofembodiments of the present invention relate to a foldable displayapparatus and a portable terminal.

2. Description of the Related Art

In recent years, a curved or folded display panel (hereinafter, referredto as a flexible display module) has been developed. The flexibledisplay module includes a flexible display panel and a variety offunctional members. The flexible display panel includes a base member, avariety of functional layers disposed on the base member, and pixelsdisposed on the base member. A rollable display apparatus or a foldabledisplay apparatus includes the flexible display module.

SUMMARY

Aspects of embodiments of the present invention provide a displayapparatus having a length that is compensable when the display apparatusis folded.

Aspects of embodiments of the present invention provide a portableterminal having the display apparatus.

According to one embodiment of the present invention, a displayapparatus includes a first base plate, a second base plate coupled tothe first base plate to allow the second base plate to be rotated on thebasis of a rotation axis between the first base plate and the secondbase plate, a moving plate coupled to the second base plate andconfigured to slide along a first direction with respect to the secondbase plate, a pop-up plate configured to move along a second directioncorresponding to a thickness direction of the second base plate on thesecond base plate in accordance with a movement of the moving plate, anda display panel including a first portion coupled to the first baseplate and a second portion coupled to the moving plate.

The display apparatus may further include an elastic member between thepop-up plate and the second base plate.

The second base plate may include a first groove configured toaccommodate the elastic member, and the pop-up plate may include asecond groove configured to accommodate the elastic member.

The moving plate may include a base portion coupled to the secondportion, a first wing portion protruding from a first side surface ofthe base portion, and a second wing portion protruding from a secondside surface of the base portion, the first wing portion and the secondwing portion being spaced apart from each other along a third directioncrossing the first direction, and the second base plate may include anaccommodating portion configured to accommodate the wing portion.

The pop-up plate may include a first upper surface having a widthcorresponding to a first length along the first direction, a firstbottom surface facing the first upper surface and having a widthcorresponding to a second length greater than the first length along thefirst direction, three first side surfaces substantially perpendicularto the first upper surface and connecting the first upper surface andthe first bottom surface, and a first inclined surface connecting thefirst upper surface and the first bottom surface.

The first length may be equal to or greater than a value obtained bymultiplying a shortest distance between the rotation axis and thedisplay panel by pi (π).

The moving plate may include a second upper surface coupled to thesecond portion and having a width corresponding to a third length alongthe first direction, a second bottom surface facing the second uppersurface and having a width corresponding to a fourth length smaller thanthe third length along the first direction, three second side surfacessubstantially perpendicular to the second upper surface and connectingthe second upper surface and the second bottom surface, and a secondinclined surface connecting the second upper surface and the secondbottom surface, and a first angle between the first inclined surface andthe first bottom surface is substantially equal to a second anglebetween the second inclined surface and the second upper surface.

A corner at which one side surface among the first side surfaces, whichfaces the first inclined surface, may be connected to the first bottomsurface has a round shape.

The second base plate may include a bottom portion on which the pop-upplate and the moving plate are disposed and a sidewall portion extendingin the second direction from the bottom portion, and the bottom portionmay include a stepped portion defined therein to accommodate the pop-upplate.

The second base plate may further include a protrusion portionprotruding from an inner surface of the sidewall portion and the firstupper surface of the pop-up plate may include a recess formed therein toaccommodate the protrusion portion.

The bottom portion may include an exposure portion that is exposed whenthe moving plate moves when the second base plate rotates.

One base plate of the first and second base plates may have asubstantially cylindrical shape elongated in a third direction crossingthe first direction, the other base plate of the first and second baseplates may include a second coupling portion coupled to both ends of thefirst coupling portion, which are spaced apart from each other in thethird direction, and a third portion of the display panel, which isdefined between the first and second portions, may be wound around thefirst coupling portion in accordance with a rotation of the second baseplate.

The moving plate may have a first strength and the pop-up plate may havea second strength smaller than the first strength.

When a case that a rotation angle of the second base plate is 0 and thedisplay panel is flat is referred to as a first state and a case thatthe rotation angle of the second base plate is 180 and the display panelis folded is referred to as a second state, the moving plate may slidetoward the rotation axis while the second base plate rotates from thefirst state to the second state.

The pop-up plate may be pressed down and the moving plate may slideabove the pop-up plate while the second base plate rotates to the secondstate from the first state.

According to one embodiment of the present invention, a portableterminal including a display panel deformed from one state to anotherstate among a first state in which the display panel is flat and asecond state in which the display panel is folded, a first base platecoupled to a first portion of the display panel, a moving plate coupledto a second portion of the display panel, the second portion beingspaced apart from the first portion along a first direction, a pop-upplate configured to support a third portion of the display panel whenthe display panel is in the first state, the third portion of thedisplay being between the first and second portions, and a second baseplate coupled to the first base plate and configured to be rotatedrelative to the first base plate, the second base plate beingsliding-coupled to the moving plate and configured to accommodate thepop-up plate.

The moving plate may be configured to slide toward the pop-up plate andthe pop-up plate may be configured to be accommodated in the second baseplate by the moving plate when the state of the display panel is changedfrom the first state to the second state.

The pop-up plate may include a first inclined surface contacting asecond inclined surface of the moving plate when the display panel is inthe first state, the first inclined surface may have an incline at afirst angle with respect to a bottom surface of the pop-up plate, thesecond inclined surface may have an incline at a second angle withrespect to an upper surface of the moving plate, and each of the firstand second angles may be an acute angle.

The pop-up plate may be disposed between the moving plate and the secondbase plate when the display panel is in the second state.

The third portion may be bent at a first radius of curvature when thedisplay panel is in the second state, and a width in the first directionof the third portion is equal to or greater than a value obtained bymultiplying the first radius of curvature by pi (π) when the displaypanel is in the first state.

According to the above, the stress applied to the display panel, whichis caused when the display apparatus and the portable terminal arefolded, may be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other advantages of embodiments of the present inventionwill become readily apparent by reference to the following detaileddescription when considered in conjunction with the accompanyingdrawings wherein:

FIG. 1 is a perspective view showing a display apparatus according to anexample embodiment of the present invention;

FIG. 2 is an exploded perspective view showing the display apparatusshown in FIG. 1;

FIG. 3 is a cross-sectional view taken along a line I-I′ of FIG. 1;

FIG. 4 is a cross-sectional view taken along a line II-II′ of FIG. 1when a display apparatus is in a first state according to an exampleembodiment of the present invention;

FIG. 5 is a cross-sectional view showing a state of a display apparatus,which is changed to a second state from a first state, according to anexample embodiment of the present invention;

FIG. 6 is a cross-sectional view showing a display apparatus in a secondstate according to an example embodiment of the present invention;

FIG. 7 is a plan view showing a display apparatus in a second stateaccording to an example embodiment of the present invention; and

FIG. 8 is an exploded perspective view showing a display apparatusaccording to an example embodiment of the present invention.

DETAILED DESCRIPTION

Hereinafter, example embodiments of the present invention will bedescribed with reference to accompanying drawings. In the followingdescription, the same reference numerals will be assigned to elementsand structures identical to those of the related art and detaileddescription thereof will be omitted in order to avoid redundancy.Although the example embodiments of the present invention have beendescribed, it is understood that the present invention should not belimited to these example embodiments but various changes andmodifications can be made by one ordinary skilled in the art within thespirit and scope of the present invention as hereinafter claimed.

Hereinafter, the present invention will be explained in detail withreference to the accompanying drawings.

FIG. 1 is a perspective view showing a display apparatus DD according toan example embodiment of the present invention.

FIG. 1 shows a foldable portable terminal as the display apparatus DD,but the display apparatus DD should not be limited thereto or thereby.For example, the display apparatus DD may be applied to a large-sizedelectronic item, such as a foldable television set, etc., and a smalland medium-sized electronic item, such as a personal computer, anotebook computer, a personal digital assistant (PDA), a game unit, amobile electronic device, a wrist-type electronic device (e.g., a smartwristwatch), a camera, etc., but embodiments of the present inventionare not limited thereto or thereby.

The display apparatus DD includes a display panel DP, a first base plateBP1, a second base plate BP2, a moving plate MP (refer to FIG. 2), and apop-up plate PP (refer to FIG. 2).

The display panel DP displays an image in response to signals appliedthereto. Hereinafter, an organic light emitting display panel will bedescribed as the display panel DP, but the display panel DP should notbe limited to the organic light emitting display panel as long as thedisplay panel DP has flexibility.

The display panel DP may be flexible. Accordingly, a base substrateincluded in the display panel DP may be a flexible substrate and includea plastic material having superior heat resistance and durability, suchas polyethylene etherphthalate, polyethylene naphthalate, polycarbonate,polyarylate, polyetherimide, polyethersulfone, polyimide, etc, butembodiments of the present invention are not limited thereto or thereby.For example, the base substrate may be a film, which is not damaged eventhough the base substrate is curved (e.g., a film that is not damagedwhen it is bent or flexed).

The display panel DP includes a first electrode, a second electrode, andan organic layer. The first electrode is an anode electrode (a positiveelectrode). The first electrode generates holes. The second electrode isa cathode electrode (a negative electrode). The second electrodegenerates electrons. The organic layer includes a plurality of layersand includes an organic material. The organic layer includes an organiclight emitting layer including a low molecular weight or high molecularweight organic material. The holes and the electrons are injected intothe organic light emitting layer from the first and second electrodes,respectively, and are recombined in the organic light emitting layer togenerate excitons, and the organic light emitting display panel emits alight by the excitons that return to a ground state from an excitedstate.

According to one embodiment of the present invention, the displayapparatus DD may further include a touch sensing unit disposed on thedisplay panel DP. The touch sensing unit may be classified as aresistive film type, an electrostatic capacitive type, and anelectromagnetic induction type depending on its operational principle.In the case where the touch sensing unit is the electrostatic capacitivetype touch sensing unit, the touch sensing unit includes two kinds ofsensors crossing each other. The electrostatic capacitive type touchsensing unit obtains coordinate information in a self-capacitance schemeor a mutual capacitance scheme.

The first base plate BP1 and the second base plate BP2 are coupled toeach other such that the first and second base plates BP1 and BP2 rotatewith respect to each other. In a case where at least one of the firstand second base plates BP1 and BP2 rotates, the display panel DP isfolded with respect to (e.g., along) a folding axis Fx.

FIG. 2 is an exploded perspective view showing the display apparatusshown in FIG. 1 and FIG. 3 is a cross-sectional view taken along a lineI-I′ of FIG. 1.

Referring to FIGS. 2 and 3, the display panel DP includes a firstportion AR1, a second portion AR2, and a third portion AR3. The firstportion AR1 is spaced apart from the second portion A2 in or along afirst direction DR1. The third portion AR3 is between the first portionAR1 and the second portion AR2.

When the display panel DP is folded, the first and second portions AR1and AR2 are not folded (or not bent) and the third portion AR3 is folded(or bent). In some embodiments, display panel DP may have flexibilityover the entire area thereof or, in other embodiments, only the foldedthird portion AR3 may have flexibility.

The first portion AR1 of the display panel DP is coupled to the firstbase plate BP1 and the second portion AR2 of the display panel DP iscoupled to the moving plate MP. The pop-up plate PP supports the thirdportion AR3 of the display panel DP when the display panel DP is in aflat state. The second base plate BP2 is coupled to the first base plateBP1 to allow the second base plate BP2 to be rotatable relative to thefirst base plate BP1, and the second base plate BP2 is slide-coupled tothe moving plate MP.

The second base plate BP2 includes a bottom portion BP and a sidewallportion SW. The moving plate MP and the pop-up plate PP are disposed onthe bottom portion BP. The sidewall portion SW extends from the bottomportion BP along a second direction DR2.

The bottom portion BP is provided with a stepped portion SP on which thepop-up plate PP is disposed and an exposure portion EP exposed when themoving plate MP moves. The stepped portion SP has a thickness thinnerthan that of a portion of the bottom portion BP on which the movingplate MP slides. When the moving plate MP slides, the pop-up plate PP iseasily inserted into the stepped portion SP under the moving plate MP.

The moving plate MP slides with respect to the second base plate BP2along the first direction DR1. The moving plate MP includes a baseportion SB and a wing portion PB. The base portion SB is coupled to thesecond portion AR2. The wing portion PB protrudes from side surfacesspaced apart from each other along a third direction DR3 crossing thefirst direction DR1. The sidewall portion SW of the second base plateBP2 includes an accommodating portion AC formed therein to accommodatethe wing portion PB.

In the present example embodiment, the wing portion PB protrudes fromthe side surfaces of the base portion SB, but embodiments of the presentinvention are not be limited thereto or thereby. For instance, in oneembodiment, the second base plate BP2 and the moving plate MP arecoupled to each other such that the second base plate BP2 and the movingplate MP slide with respect to each other. According to anotherembodiment, a wing portion may protrude from an inner surface of thesidewall portion SW and the base portion BS may include an accommodatingportion formed therein to accommodate the wing portion. According toanother embodiment, the wing portion may protrude from a bottom surfaceof the base portion SB and the second base plate BP2 may include anaccommodating portion formed therein to accommodate the wing portion.

The pop-up plate PP is disposed on the stepped portion SP. The pop-upplate PP is configured to move along the second direction DR2corresponding to a thickness direction of the second base plate BP2. Forinstance, when the moving plate MP slides along the first direction DR1,the pop-up plate PP rises up or falls down along the second directionDR2.

The moving plate MP may further include a protrusion portion PTprotruding from an inner surface of the sidewall portion SW. Theprotrusion portion PT may protrude from an inner surface of the sidewallportion SW adjacent to the pop-up plate PP. The protrusion portion PTcontrols the rising of the pop-up plate PP along the second directionDR2.

The pop-up plate PP includes a first upper surface US1, a first bottomsurface BS1, three first side surfaces SS1, and a first inclined surfaceIS1.

A width of the first upper surface US1, which is substantially parallelto the first direction DR1, has a first length L1 along the firstdirection DR1. The first upper surface US1 makes contact with the thirdportion AR3 of the display panel DP when the display panel DP is in theflat state. The first bottom surface BS1 faces away from the first uppersurface US1. A width of the first bottom surface BS1, which issubstantially parallel to the first direction DR1, has a second lengthL2 along the first direction DR1. The second length L2 is greater thanthe first length L1. A cross-section of the pop-up plate PP, which issubstantially parallel to a plane surface defined by the first andsecond directions DR1 and DR2, has a substantially trapezoidal shape.

Each of the first side surfaces SS1 connects the first upper surface US1to the first bottom surface BS1. Each of the first side surfaces SS1 issubstantially perpendicular to the first upper surface US1. The firstinclined surface IS1 connects the first upper surface US1 to the firstbottom surface BS1. Because the width in the first direction DR1 of thefirst upper surface US1 is different from the width in the firstdirection DR1 of the first bottom surface BS1, the first inclinedsurface IS1 is not perpendicular to the first upper surface US1. A firstangle AG1 between the first bottom surface BS1 and the first inclinedsurface IS1 may be an acute angle smaller than 90 degrees (and an anglebetween the first top surface US1 and the first inclined surface IS1 maybe an obtuse angle larger than 90 degrees).

A corner portion CP, at which one side surface facing the first inclinedsurface IS1 among the first side surfaces SS1 is connected to the firstbottom surface BS1, may have a round (or rounded) shape. When the pop-upplate PP rises up or falls down along the second direction DR2, frictionand interference between the pop-up plate PP and a coupling portion CM1may be reduced due to the round shape.

An elastic member ET is disposed between the pop-up plate PP and thestepped portion SP. The elastic member ET may be a spring, a siliconerubber, a natural rubber, or a synthetic rubber. The material for theelastic member ET is not limited to a specific material as long as theelastic member ET is compressed when an external force is applied to theelastic member ET and returns its original shape when the external forceis removed.

The stepped portion SP may include a first groove GV1 formed therein toaccommodate the elastic member ET. The elastic member ET may be morestably fixed by the first groove GV1. In the present example embodiment,the first groove GV1 has a substantially circular shape, but embodimentsof the present invention are not limited thereto or thereby. Forinstance, the first groove GV1 may have a shape that is deformeddepending on the shape of the elastic member ET. When the elastic memberET has a substantially rectangular shape of silicone rubber, the firstgroove GV1 has a substantially rectangular shape.

The pop-up plate PP may include a second groove GV2 formed in the firstbottom surface BS1 to accommodate the elastic member ET. In the presentexample embodiment, the second groove GV2 may have substantially thesame shape as an external shape of the pop-up plate PP. For example, aninner portion of the pop-up plate PP may be hollow. When the secondgroove GV2 is formed in the first bottom surface BS1 of the pop-up platePP, a weight of the display apparatus DD may be reduced. As another way,the second groove GV2 may have a shape corresponding to that of theelastic member ET. In addition, at least one of the first groove GV1 andthe second groove GV2 may be omitted according to embodiments.

The first upper surface US1 of the pop-up plate PP may include a recessHM formed therein to accommodate the protrusion portion PT of the secondbase plate BP2. In the present example embodiment, the recess HM isprovided at two corners of the first upper surface US1, but embodimentsof the present invention are not limited thereto or thereby. When thepop-up plate PP rises up in the second direction DR2, the protrusionportion PT is accommodated in the recess HM, and thus the rising of thepop-up plate PP in the second direction DR2 is controlled. Accordingly,the third portion AR3 may be prevented from being separated by thepop-up plate PP when the display panel DP is in the flat state.

The moving plate MP includes a second upper surface US2, a second bottomsurface BS2, three second side surfaces SS2, and a second inclinedsurface IS2.

A width of the second upper surface US2, which is substantially parallelto the first direction DR1, has a third length L3 along the firstdirection DR1. The second upper surface US2 is coupled to the secondportion AR2 of the display panel DP. The second bottom surface BS2 facesthe second upper surface US2. A width of the second bottom surface BS2,which is substantially parallel to the first direction DR1, has a fourthlength L4 along the first direction DR1. The fourth length L4 is smallerthan the third length L3. A cross-section of the moving plate MP, whichis substantially parallel to a plane surface defined by the first andsecond directions DR1 and DR2, has a substantially trapezoidal shape.

Each of the second side surfaces SS2 connects the second upper surfaceUS2 and the second bottom surface BS2. Each of the second side surfacesSS2 is substantially perpendicular to the second upper surface US2. Thesecond inclined surface IS2 connects the second upper surface US2 andthe second bottom surface BS2. Because the width in the first directionDR1 of the second upper surface US2 is different from the width in thefirst direction DR1 of the second bottom surface BS2, the secondinclined surface IS2 is not perpendicular to the second upper surfaceUS2. A second angle AG2 between the second upper surface US2 and thesecond inclined surface IS2 may be an acute angle smaller than 90degrees (and the angle between the second bottom surface BS2 and thesecond inclined surface may be an obtuse angle greater than 90 degrees).

The first angle AG1 may be substantially the same as the second angleAG2. The first inclined surface IS1 makes contact with the secondinclined surface IS2 when the display panel DP is in the flat state. Insome embodiments of the present invention, at least one of the first andsecond inclined surfaces IS1 and IS2 may include a member to reducefriction, which is attached thereto.

The first base plate BP1 and the second base plate BP2 are coupled toeach other such that the first base plate BP1 and the second base plateBP2 rotate with respect to each other. The first base plate BP1 includesthe first coupling portion CM1 and the second base plate BP2 includes asecond coupling portion CM2. The first coupling portion CM1 and thesecond coupling portion CM2 are coupled to each other by a rotation axisRA (or hinge).

In the present example embodiment, the rotation axis RA is coupled tothe second coupling portion CM2 after penetrating through the firstcoupling portion CM1, but embodiments of the present invention are notlimited thereto or thereby. For instance, a protrusion is provided atone surface of surfaces of the first and second coupling portions CM1and CM2, which make contact with each other, and a recess is provided atthe other surface of the surfaces of the first and second couplingportions CM1 and CM2. Therefore, the first and second coupling portionsCM1 and CM2 are coupled to each other.

The first coupling portion CM1 may have a substantially cylindricalshape elongated along the third direction DR3. The second couplingportion CM2 is coupled to both ends of the first coupling portion CM1,which are spaced apart from each other along the third direction DR3.When the display panel DP is folded, the third portion AR3 is woundaround the first coupling portion CM1. A length DS of the third portionAR3 is equal to or greater than a value obtained by multiplying a radiusHR of the first coupling portion CM1 by pi (π).

The third portion AR3 is wound around the first coupling portion CM1 andthe moving plate MP slides toward the rotation axis RA. The moving plateMP pushes out the pop-up plate PP, and thus the pop-up plate PP fallsalong the second direction DR2. Thus, the pop-up plate PP is insertedinto or slid under the moving plate MP and the moving plate MP slides tobe adjacent to the first coupling portion CM1. Although the thirdportion AR3 is wound around the first coupling portion CM1, a stressapplied to the display panel DP is reduced by the movement of the pop-upplate PP and the moving plate MP.

FIG. 4 is a cross-sectional view taken along a line II-II′ of FIG. 1when the display apparatus DD is in a first state according to anexample embodiment of the present invention.

Referring to FIGS. 3 and 4, when the display panel DP is in the firststate, a rotation angle of the second base plate BP2 is about zero (0).During the first state, the first inclined surface IS1 of the pop-upplate PP and the second inclined surface IS2 of the moving plate MP aremaintained in a contact state.

The pop-up plate PP supports the third portion AR3 of the display panelDP. For example, because the hollow space under the third portion AR3 issupported by the pop-up plate PP in the first state, the third portionAR3 may be prevented from being damaged even though an external force isapplied to the third portion AR3.

Hereinafter, a length of a first section of the first base plate BP1 isreferred to as a first length LB1. The first section corresponds to asection in which the first base plate BP1 is overlapped with the firstportion AR1 when the display panel DP is in the first state. The firstlength LB1 may be substantially the same as the length in the firstdirection DR1 of the first portion AR1.

A length of a second section of the second base plate BP2 is referred toas a second length LB2. The second section corresponds to a section inwhich the second base plate BP2 is overlapped with the second and thirdportions AR2 and AR3 when the display panel DP is in the first state.The second length LB2 may be substantially the same as the lengthobtained by adding the length in the first direction DR1 of the secondportion AR2 and the length in the first direction DR1 of the thirdportion AR3.

In the first state, the first upper surface US1 of the pop-up plate PPand the second upper surface US2 of the moving plate MP may be locatedat the same plane surface. The pop-up plate PP may be prevented orblocked from rising higher than the moving plate MP by the protrusion PTshown in FIG. 2. Accordingly, the third portion AR3 of the display panelDP may be prevented or blocked from protruding in the first state.

FIG. 5 is a cross-sectional view showing a state of a display apparatus,which is changed to a second state from a first state, according to anexample embodiment of the present invention and FIG. 6 is across-sectional view showing a display apparatus in a second stateaccording to an example embodiment of the present invention.

Referring to FIGS. 5 and 6, the second base plate BP2 may be rotatedrelative to the first base plate BP1. Hereinafter, a state in which therotation angle of the second base plate BP2 is about 180 degrees asshown in FIG. 6 is referred to as a second state. In this case, thedisplay panel DP is folded.

In the present example embodiment, the display apparatus DD may beoutwardly folded when the second base plate BP2 rotates in a clockwisedirection in the first state. In the case where the display apparatus DDis outwardly folded, a display area of the display panel DP faces towardoutside even though the display panel DP is in the second state.Therefore, a user may view the image displayed on the display panel DPeven though the display panel DP is folded.

FIG. 5 shows the case that the rotation angle of the second base plateBP2 is a first angle AT. When the second base plate BP2 rotates by thefirst angle AT, a third section is further provided between the firstand second sections. The third section corresponds to a portion of thefirst coupling portion CM1, which makes contact with the display panelDP.

A third length LB3 of the third section may be substantially the same asa value CCP, which is obtained by the following Equation 1. HR is theradius of the first coupling portion CM1, and AT is the rotation angleof the second base plate BP2.

$\begin{matrix}{{CCP} = {2\pi \times {HR} \times \frac{AT}{360}}} & {{Equation}\mspace{14mu} 1}\end{matrix}$

The length of the display panel DP may be substantially equal to a sumof the first length LB1 of the first section and the second length LB2of the second section. In the case where the third section is furtherprovided between the first and second sections according to the rotationof the second base plate BP2, a portion of the third portion AR3 of thedisplay panel DP is wound around the third section. Because the thirdsection is further provided, the moving plate MP slides with respect tothe second base plate BP2 along a direction toward the second base plateBP2.

The moving plate MP slides by a first distance DT1. The first distanceDT1 may be substantially the same as the third length LB3. When thesecond base plate BP2 rotates, the moving plate MP slides. Accordingly,the stress applied to the display panel DP may be reduced by the thirdsection.

The moving plate MP applies force or pressure to the pop-up plate PPwhile sliding and the pop-up plate PP falls or moves down (or is presseddown) along the second direction DR2 corresponding to the thicknessdirection of the second base plate BP2. In the first state, the firstinclined surface IS1 of the pop-up plate PP is inclined with respect toand makes contact with the second inclined surface IS2 of the movingplate MP. Therefore, the pop-up plate PP falls down along the seconddirection DR2 by the pushing force of the moving plate MP.

The moving plate MP has a first strength and the pop-up plate PP has asecond strength. The first strength is greater than the second strength.The moving plate MP includes a stainless steel or a reinforced plastic,and the pop-up plate PP includes a plastic material having the strengthweaker than that of the stainless steel or the reinforced plastic. Whenthe first strength is greater than the second strength, the pushingforce caused by the moving plate MP and applied to the pop-up plate PPmay be greater than the pushing force caused by the pop-up plate PP andapplied to the moving plate MP. As a result, the pop-up plate PP movesrelatively easily. However, according to some embodiments, the movingplate MP and the pop-up plate PP may include the same material as eachother.

According to a comparative example, in the case where the moving plateMP does not slide, the display panel DP is stretched by the length ofthe third section. As a result, a tensile force occurs in the displaypanel DP and components included in the display panel DP may be damaged.However, according to the present example embodiment, the display panelDP is not stretched by the third length LB3 of the third section eventhough the third length LB3 of the third section is changed. Forinstance, the moving plate MP slides by the third length LB3 of thethird section and the second portion AR2 moves to correspond to thewound length of the display panel DP. Accordingly, the tensile forceoccurring in the display panel DP may be reduced, and thus the stressapplied to the display panel DP when the display panel DP is folded maybe reduced. In addition, because the pop-up plate PP supports the thirdportion AR3 when the display panel DP is in the first state, the thirdportion AR3 may be protected from being damaged due to the externalforce.

FIG. 6 shows the case that the second base plate BP2 rotates by about180 degrees. A third distance LB3 a between the first and secondsections may be substantially equal to a value obtained by multiplyingthe radius HR of the first coupling portion CM1 by the pi (π). Forexample, the length of the third portion AR3 of the display panel DPwound around the third section may be substantially equal to the valueobtained by multiplying the radius HR of the first coupling portion CM1by pi (π).

The moving plate MP slides by the third length LB3 a of the thirdsection provided between the first and second sections. A distance DT2along which the moving plate MP slides may be substantially the same asthe third length LB3 a.

When the second base plate BP2 rotates in a counter-clockwise direction,the state of the display panel DP is changed to the first state from thesecond state. In the case where the state of the display panel DP ischanged to the first state from the second state, the moving plate MPslides in a direction away from the rotation axis RA.

Because the display panel DP tends to return to its original shape by arestoration force when the state of the display panel DP is changed tothe first state, the moving plate MP slides to the direction far awayfrom the rotation axis RA. Therefore, a separate elastic member forrestoring the position of the moving plate MP may be omitted.

FIG. 7 is a plan view showing the display apparatus DD in the secondstate according to an example embodiment of the present invention.

Referring to FIG. 7, the moving plate MP (refer to FIG. 6) slides whenthe display panel DP is folded, and thus the exposure portion EP of thesecond base plate BP2 is exposed to the outside.

According to the present example embodiment, a variety of members may bedisposed on the exposure portion EP. For instance, a pattern (e.g., apredetermined pattern) may be printed on the exposure portion EP or afilm printed with a pattern (e.g., a predetermined pattern) may beattached to the exposure portion EP, but embodiments of the presentinvention are not limited thereto or thereby. In addition, in someembodiments of the present invention, a sub-display panel may bedisposed on the exposure portion EP according to another embodiment. Thesub-display panel may be exposed to the outside when the second baseplate BP2 rotates.

FIG. 8 is an exploded perspective view showing a display apparatus DD1according to an example embodiment of the present invention.

Referring to FIG. 8, the display apparatus DD1 have the same structureand function as those of the display apparatus DD shown in FIG. 2 exceptfor a first base plate BP1 a and a second base plate BP2 a.

The first base plate BP1 a includes a first coupling portion CM1 a andthe second base plate BP2 a includes a second coupling portion CM2 a.The first coupling portion BP1 a is coupled to the second couplingportion BP2 a by a rotation axis RA.

The second coupling portion CMb has a substantially cylindrical shapeelongated in the third direction DR3. The first coupling portion CMa iscoupled to both ends of the second coupling portion CMb, which arespaced apart from each other. When the second base plate BP2 a rotates,the third portion AR3 of the display panel DP is wound around the secondcoupling portion CMb.

A first surface US1 of the pop-up plate PP has a first length L1. In thepresent example embodiment, the first length L1 is equal to or greaterthan a value obtained by multiplying a shortest distance HR between thedisplay panel DP and the rotation axis RA by pi (π). Accordingly, themoving plate MP may slide by the third section elongated when the thirdportion AR3 of the display panel DP is wound around the second couplingportion CMb.

Although the example embodiments of the present invention have beendescribed, it is understood that the present invention should not belimited to these example embodiments but various changes andmodifications can be made by one ordinary skilled in the art within thespirit and scope of the present invention as hereinafter claimed.

What is claimed is:
 1. A display apparatus comprising: a first baseplate; a second base plate coupled to the first base plate to allow thesecond base plate to be rotated on the basis of a rotation axis betweenthe first base plate and the second base plate; a moving plate on thesecond base plate and configured to slide along a first direction withrespect to the second base plate; a pop-up plate on the second baseplate; an elastic member between the pop-up plate and the second baseplate; and a display panel coupled to the first base plate and themoving plate; wherein the pop-up plate is configured to move along asecond direction perpendicular to the first direction with respect tothe second base plate while the moving plate slides along the firstdirection with respect to the second base plate, and wherein the elasticmember is configured to bias a position of the pop-up plate along thesecond direction; wherein the second base plate comprises a bottomportion, the pop-up plate and the moving plate being on the bottomportion, the bottom portion comprising a stepped portion defined thereinto accommodate the pop-up plate.
 2. The display apparatus of claim 1wherein a thickness of a region in which the stepped portion of thebottom portion is defined is thinner than a thickness of a region inwhich the stepped portion is not defined.
 3. The display apparatus ofclaim 1, wherein the stepped portion comprises a groove configured toaccommodate the elastic member.
 4. The display apparatus of claim 3,wherein the groove has a shape corresponding to a shape of the elasticmember.
 5. The display apparatus of claim 1, wherein a bottom surface ofthe pop-up plate comprises a groove configured to accommodate theelastic member.
 6. The display apparatus of claim 5, wherein the groovehas substantially same shape as an external shape of the pop-up plate.7. The display apparatus of claim 5, wherein the groove has a shapecorresponding to a shape of the elastic member.
 8. The display apparatusof claim 1, wherein the elastic member comprises a spring, a siliconerubber, a natural rubber, or a synthetic rubber.
 9. The displayapparatus of claim 1 wherein the moving plate is configured to slidebetween a first configuration and a second configuration along the firstdirection with respect to the second base plate, the moving plate beingaway from the rotation axis in the first configuration and beingadjacent the rotation axis in the second configuration, the pop-up plateis configured to move in a direction toward the stepped portion from thedisplay panel when the moving plate slides to change the firstconfiguration to the second configuration, and the pop-up plate isconfigured to move in a direction toward the display panel from thestepped portion when the moving plate slides to change the secondconfiguration to the first configuration.